The Cockroach Life Cycle and Behavior
As with many animals, cockroach reproduction relies on eggs from a female and sperm from a male. Usually, the female releases pheromones to attract a male, and in some species, males fight over available females. But exactly what happens after the male deposits his sperm into the female varies from species to species.
Most roaches are oviparous -- their young grow in eggs outside of the mother's body. In these species, the mother roach carries her eggs around in a sac called an ootheca, which is attached to her abdomen. The number of eggs in each ootheca varies from species to species. Many female roaches drop or hide their ootheca shortly before the eggs are ready to hatch. Others continue to carry the hatching eggs and care for their young after they are born. But regardless of how long the mother and her eggs stay together, the ootheca has to stay moist in order for the eggs to develop.